Aluminum alloy



atenteci Feb. 13, 19

UNITED STATES I 4 2,189,834 PATET oFFicE ALUMINUM ALLOY No Drawing.

2 Claims.

This invention relates to an improvement in aluminum alloys, and is a continuation in part of my application which will mature into U. S. Patent No. 2,157,741, May 9, 1939. More particu- 5 larly, it has in view alloys of aluminum requiring no heat treatment and having special machining .qualities, and also exhibiting desirable physical characteristics in the way of high tensile strength, suitable hardness, and a high degree of elongation. The alloys combine with these qualities a number of other advantageous characteristics, such as resistance to oxidation and corrosion. The alloys are of extremely fine grain, and machining operations result in a surface of a highly finished appearance.

These alloys, as stated, have high tensile strength and elongation without heat treatment, and while other alloys, after heat treatment involving additional expense, may show comparable tensile strength and elongation, the cost of manufacture is greater and they have the disadvantage of losing the increased physical characteristics, such as tensile strength or elongation upon being subjected to heating operations. The alloys of special heat treatment may be freely welded or subjected to heating eifects Without losing the characteristics stated. They at all times exhibit the qualities of high tensile strength and a high degree of elongation, and at the same time provide the most satisfactory material for precision machining operations.

The alloys are of very wide application industrially, and while in no way limited to use for fabrication of various structural parts for machines and the like, they are particularly suited for such use, especially in equipment requiring precision of manufacture and good appearance.

Heretcfore there have been many alloys embodying various proportions of aluminum, magnesium, copper and the like, and certain elements, such as titanium, have been used to improve the grain structure of the finished product. However, in many instances the alloys heretofore produced have involved complicated steps in alloying of the various elements, or in the development of tensile strength of the alloys through heat treatment and the like, and this expense and the incidental disadvantage of heat treatment are avoided in the present invention.

The principal object of the invention is to provide alloys wherein the aluminum content is maintained at a relatively high percentage, and wherein the other elements of the alloy are accurately proportioned to have combined action to increase the tensile strength of the finished product.

Another object of. the invention is to provide alloys of aluminum having a high degree of tensile strength without sacrificing other desirable physithe formula herein set forth when used without Application May 8, 1939, Serial No. 272,519

cal characteristics, such as high degree of elongation.

Another object of the invention is to provide aluminum alloys having high tensile strength, and a high degree of elongation and physical characteristics without the necessity of heat treatment for such product.

Another object of the invention is to provide .an aluminum alloy resistant to corrosion, and at the same time having an unusual degree of tensile strength and elongation, and adapted for machine operations to a greater degree than other alloys having like physical characteristics.

Another object of the invention is to provide an alloy of aluminum for use without heat treatment, but having a high degree of tensile strength and elongation comparable to those of heattreated alloys, whichmay be freely welded without losing such high degree of tensile strength and elongation and other physical characteristics as would be the case with alloys receiving such qualities through heat-treatment, wherein subsequent heating would destroy the original heattreating effects.

Other and further objects of the invention will appear in the course of the following description.

Some variations in the formula may be made, but a relatively high percentage of aluminum, it will be noted, is used in every instance.

Where it is desirable to have elongation at the expense of. tensile strength the following formula may be used wherein specimens have shown tensile strength of 23,000 pounds and an elongation of 18 per cent:

Where a greater degree of tensile strength is required at a sacrifice of elongation the various elements of the formula may be varied between the elements below noted:

Aluminum 93.35 to 94.95 Titanium .15 to .25 Copper 1.50 to 2.00 Tin 1.25 to 1.75 Zinc .75 to 1.75 Magnesium .40 to .90

Specimens having proportions within the limits above stated have shown a tensile strength or from 27,500 pounds to 30,000 pounds and an elongation of from 6 per cent to 8 per cent. 1

Variations may be made slightly above and below the elements set forth in the several formulas, as has been indicated, the aluminum content being the residual amount required. The exact physical results to be attributedto any particular element is not fully understood, but it is believed that the interaction of the elements added to the aluminum upon each other is clearly indicated. The titanium and tin together produce an unusually fine grained dense product having great tensile strength, and at the same time having exceptional capacity for free machining, and presenting a finished surfaceafter having been so machined. The combination of elements set forth produces an alloy in each instance of wide industrial application, which, in addition to having high tensile strength and a high degree of elongation, has fine appearance and capacity to resist oxidation and corrosive efiects. While in the instances above stated the alloys will be found satisfactory for most uses without subsequent heat-treatment, it is not intended to restrict the use of the invention to the extent that certain specialized treatment shall not be applied in the event some very unusual application of the alloys is to be made, particularly under certain high temperature conditions, or where some extraordinary specifications have to be -Iulfilled. The widespread, and almost universal use oi the alloys, without heat treatment, is provided for by the special formulas above set forth, which, as stated, have the advantage of low cost of production, and permanence of physical characteristics, when welding or like operations are carried on.

Other modes of applying the principle of my invention may be employed instead of those explained, change being made as regards the means 1 and steps herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed,

Itherefore particularly point out and distinctly claim as my invention: a

1. An alloy of aluminum consisting of about .15 per cent of titanium, 1.50 per cent of copper, 1.25 per cent of tin, 1.75 per cent of zinc, .40 per cent of magnesium, the balance being aluminum.

2. An alloy of aluminum consisting of about .15 per cent to .25 per cent of titanium, 1.50 per cent to 2.00 per cent t copper, 1.25 per cent to 1.75 per cent of tin, .75 to 1.75 per cent of zinc, .40 to .90 per cent of magnesium, the balance beingaiuminum. V

' EDWARD A. SCHMEILER. 

